Using countd(Name), if there are several records for Name A with several zero sales, it will be wrong.

The sample data is not stored in a standard table because there is no primary key(PK). For a relational database table, there should be a PK with Order ID(or Record ID, something like that), then it is possible and reasonable for a same name with several 0 sales records. Therefore, countd(name) may lead to a wrong result.